Communicating with Watlow EZ Zone PM via RS232

[CJ_Butler__DASYLab_Pro]

Modbus didn't ship with the initial 11.00.00. It's available with 11.00.01, download from www.dasylab.com.

It should be in the Lite version. And since you don't have the formula module either, you're going to want the Modbus module.

The RS232 cannot handle MSB LSB in the LSW and MSB LSB in the MSW. We expect 4 byte formats to be LSW (LSB MSB) MSW (LSB MSB) or MSW (MSB LSB) LSW (MSB LSB).

Your device is doing LSW (MSB LSB) MSW (MSB LSB).

If you have any problems with that, then use the support form at www.dasylab.com to contact us directly. Actually... thinking about it, do the download, AND immediately contact us.

[pirates712]

Yes! The modbus analog input is doing the trick, almost. When I use the "test" feature, it returns the correct value, but when I connect the output to a digital meter I get very small numbers (should be in the 24-25 range for room temp)

[CJ_Butler__DASYLab_Pro]

You'll need to contact support by phone. If you're in the US, use the www.dasylab.com support form, or call Measurement Computing at 508-946-5100.

[Watlow]

Keep in mind that the EZ-ZONE PM sends all data in degrees F unless you specifically change the units using a Modbus command. Also, the Modbus word order by default is Low Word, High Word. You may change this in the Setup Page, Comms menu. Contact Watlow technical support at 507-494-5656 for details concerning the EZ-ZONE PM or access to Modbus tools for testing the PM separate from DasyLab. The tools available from the Watlow web site will show the data transactions between the PM and PC. This can be used to see what packets contain. Ensure that the PM has the latest firmware which currently is revision 10.0

- RGH

[pirates712]

It was solved by replacing a .dll with one supplied by DASYLab that allowed me to switch the word order.

[Kaztyel]

Which Modbus command should I use to specify the EZ-ZONE PM to send all data in Celsius Degrees, and not in Fahrenheit? I can not find it and I´ve been looking everyhere!

[Watlow]

The Series 96 sends data in 16-bit integer assumed decimal format. The EZ-ZONE PM sends data in 32-bit floating point format. Be sure to read two consecutive registers and interpret as a float. In addition, the default data format is in degrees Fahrenheit. To have communications in degrees Celsius, send a Modbus command to the register that changes communications display units. These units are independent from the LED display units.

Watlow Technical Support

[Watlow]

The Modbus register to change the display units of Communications Port 2 is 2510 for Map 1 and 2990 for Map 2. Send 30 for degrees F or 15 for degrees C. See page 98 of the EZ-ZONE PM Integrated User's Manual, Revision L. The Map specifies which parameters will be available. As Watlow has added features, new Modbus registers were required so rather than add to the original Modbus Map (set of registers), Watlow choose to create a second set with the Modbus registers re-organized. We suggest using Map 2 unless you need compatibility with an earlier PM model.

Watlow Technical Support

[CJ_Butler__DASYLab_Pro]

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[Michelox]

Could someone tell me what is the best substitute Watlow Series 96 to connect RS- 232 and EZ zone I set and I get a fixed temperature value