View Full Version : DNC Questions about MHP B-22 with Hydrapath III

Jim Estes
05-04-2005, 08:03 AM
I have an MHP B-22 machining center with a Hydrapath III control. I can DNC to the machine but only at 2400 bps. There is an option to set the baud rate at 4800 and 9600 bps. But when I do that, it is very unreliable, I get errors and the program stops. Does anyone know about this control specifically? Any suggestions on how to get it to work properly would be greatly appreciated. After getting BobCad-Cam V20 and getting into the 3D milling, I need to speed the machine up to keep up with me programming.

Also, I wasn't sure I had my RS-232 Cable made properly, so I ordered one from Shop Floor Automation, they sent me two different connectors to connect to the machine, one of them works and the other one doesn't with the settings that I used.

So if anyone knows the Hydrapath III, I'd really appreciate some help.



05-04-2005, 11:06 AM
I don't know the Hydrapath III but is the serial cable fully populated or is the hardware hanshake jumpered, if so the cable will have only 3 conductors between ends and this does not allow hardware handshake. Also there is the ability on most systems to also use software handshake by inserting start/stop codes into the transmission. Often if some kind of handshake is used the higher baud rates can be used.

Jim Estes
05-11-2005, 11:27 PM
I recieved a phone call yesterday about this machine, from a member of CNC Zone. He advised me to check the "buffer" for the COM prot that I was using to DNC to the machine. I turned the buffer off (in win98) and now the machine works great with 9600 BPS. I just wanted to say thank you, I will not mention his name but he was dead on with his advice.


06-01-2005, 12:41 PM
050601-1133 EST USA


It is great that your problem was solved.

At 9600 baud and short fast strokes does your CNC hesitate? or do you slow the feed rate down to eliminate the intermittent operation?

If the CNC allows, then have you tried higher baud rates? or can you add an option to increase baud rate?


Jim Estes
06-01-2005, 01:20 PM
Unfortunately 9600 BPS is the highest option available for this machine as it is. I could opt for a control upgrade, but right now I am getting my money's worth. At 9600 bps I only notice a slight hesitation when cutting 3d contours in graphite for electrodes that are less than about 2 square inches. With only a 5000 rpm spindle I can't feed nearly as fast in steel so that is not a problem. Cutting aluminum with very small endmills isn't a problem either because I have to slow the feedrate down to keep from breaking the cutter. I am about at the limits of speed for this machine, but I am much faster than I used to be at 2400 bps. Also, since turning off the FIFO buffer for the COM port I haven't had a single error while sending programs, that alone saves me tons of time.


11-28-2005, 10:25 AM
I may have a manual for the Hydrapath III. Also there is company here in Buffalo that should be able to answer any questions about the MHP machine. They are called AMT machines. http://www.amtmachs.com/.
Let me know if you would like a copy of the manual


05-20-2009, 03:14 PM
hi there were trying to post from bob cad v23 to our mhp s-24 machining center and aren't having any luck at all with it weve broguht up the load screen but every time we try to post they dont seem to reconize each other

Jim Estes
05-21-2009, 12:26 AM
I had a lot of trouble figuring out how to DNC to my B-22 machine. I had cable problems, so I bought my DNC cable from www.shopfloorautomations.com, worked perfect for me.

I had a few problems with the settings, both at the machine and at the PC.

I finally got the DNC to work, but there are some very specific things that need to be done in order to get very long programs to run.

If you would like the information, I can e-mail you a couple of pages of very specific things to do in order to get it to work.

Jim Estes
05-21-2009, 08:47 AM
Here is a PDF file of the information that I have compiled from years of working with BobCad and the MHP machine. I hope it helps.

The BobCad setup is for version 21, I don't have V23 so I don't know the exact setup for that. I have the settings for Predator, but at the moment it is busy sending a very long program to my machine, when it is finished I will post a screen shot of the setting to send from Predator.


05-25-2009, 10:36 AM
im going to look over the pdf and have another go at it ill let you know how i make out today. took the weekend off to cool down :P

05-25-2009, 02:54 PM
still trying to completely figure it out our machine doesn't seem to like job number 99. but i have a feelng it could maybe be our rs-232 cable. if you could get me the pictures it would be great. our machine is a s-24 but so far all the screens were like your pdf

05-25-2009, 07:58 PM
Here's another stymied operator. Trying to get DNC working from Predator to a HydraPath III.

Comp is modern, usb to serial. I've spent hours fiddling with the extensive settings, no dice. The farthest I've gotten is an "IMPROPERLY FORMATTED TAPE" error.. which I think means that it's receiving data, just not properly-formatted data.

I'm also getting an ILLEGAL JOB NUMBER when I put in 99.

Jim Estes
05-26-2009, 09:22 AM
Here is the screenshots of the setup for Predator to Hydrapath III. I am not sure whether the DNC option is available for ALL Hydrapath III machines, but it works on mine.

There is also one more thing I remembered must be done. There must be a program in the machine memory to go along with the Pattern in memory.
The number 99 is the program number for DNC, but you must also have a valid Pattern number in memory. In order to have a valid pattern, you must have a program saved in memory that corresponds to that pattern. I keep a simple one line program saved in memory under the program # 2, and I use the pattern # 2. This allows me to save my offsets to Job #2. When you put in 99 for the Job #, you must put in the valid pattern #, (i.e 2).

I hope this helps.

05-26-2009, 02:39 PM
I almost think my HydraPath III doesn't have the memory to expand to the 99th program needed for DNC.. the previous owner said he had it working, though.

I can't create or edit a job #99.. just 1-10. Can't even edit #11 after each of the first ten have a rapid to 0,0,0 in them..

Jim Estes
05-26-2009, 03:07 PM
One thing occured to me that I might not have made clear in my attachments.

*****The ONLY place that Job # 99 is input is on the MAIN page.*****

The page where you RUN programs from, NOT the LOAD STORE EDIT PAGE, where you load programs into memory from.

When you are going to DNC a program, you are essentially running that program from the PC, so the Job # 99 is a signal to go and look for the program from DNC.

The Pattern must be set up as though the program in stored in at the machine, i.e pattern # 1. In order to save a pattern, you must have a program that corresponds to that pattern # in memory.

My machine will only store 10 jobs as well. From what I have been told about the Hydrapath III, if you have the RS-232 connectors, DNC will work, however, the maximum baud rate could be limited to 2400 bps. The baud rate is set on the configuration page, and both the cnc an pc must be set to the same baud rate. Mine has a maximum of 9600 bps, which is the numbers 7 entered on the configuration page.

(A=Port #1 C=Port #2) (B= Punch (or send to PC) on Port #1 D=Punch on Port #2)

Configuration numbers A-1, A-2 Enable Reader
Enter 1 to enable reader
Enter 0 to disable reader

Configuration number A-2, C-2 Baud Rate

0 for 110 baud
1 for 300
2 for 600
3 for 750
4 for 1200
5 for 2400
6 for 4800
7 for 9600

I hope this helps.

05-26-2009, 08:13 PM
HUGE help, Jim. I've got code executing on it now.

Just throws "SYSTEM ERROR READING PATTERN"s now, sometimes repeatable, sometimes not. I've tried lowering the transfer rate, same problems. The furthest I've gotten into a program is 50 lines.

Jim Estes
05-26-2009, 10:06 PM
There are lots of causes for the SYSTEM ERROR READING PATTERN. Usually, if it runs a few lines of code and then you get the error, that means that your machine and pc aren't communicating properly.

Some things to check:

FIFO buffer for the COM port should be de-activated.

Cabling may not be wired properly.

Configuration settings incorrect.

Make sure that BC isn't putting un-recognized characters into the program, (i.e, small caps, 5 decimals, odd zero's, or maybe missing decimals.)

One thing I would do, is run a program with the feedrate set to 10%, so that you know that machine isn't moving faster than the transfer of data. If the machine is just running out of data, then you have a cable problem.

You can also try running the machine in DRY RUN mode and see if the program stops sooner.

I'm glad it is working for you Vrogy.


06-03-2009, 09:51 AM
If your getting an error at the machine sending with Predator, that is good. This means the data is sent but probably in the wrong format.

Have you tried sending a program from the control back to Predator?

12-28-2009, 04:47 PM
Been a while, but I eventually got this up and running, thanks to your help. Turned out I screwed up the custom cable I made; D'oh.