Instruction Manual

Watlow Series PD ■ 62 ■ Chapter 9 Device Config. Tables

Parameter Tables

These tables contain detailed information for the all of the parameters contained in Series PD controller. The

tables consist of six fields for each parameter listed. These are:

• Parameter Name and Description - name of the parameter and a brief description. Some functions may

have more detailed information available in the Features chapters

• Web Page - web page the parameter appears on.

• Settings - blank column to allow you to document your Series PD settings.

• Range - numeric range or selection choices.

• Default - factory default values.

• Modbus - Modbus register numbers, the read/write status and the scaling factor of the Modbus value.

The parameters are grouped together by function and are in the order that they appear on the web pages. Use

the search function to find a specific parameter.

Modbus

Read/Write Status - Some parameters list the read/write status only, no Modbus register numbers. These pa-

rameters are available through the web pages only.

Modbus Registers - Some parameter values are four byte integers and require two Modbus registers. The low

To read 32-bit values:

The process value of the Series PD is contained in two registers. For example, register 31 contains the two high-

er bytes while register 32 contains the two lower bytes. The 16-bit value returned from register 31 is multiplied by

65535 and added to register 32 when working in decimal format. To place the decimal point, divide the results by

1000.

To write 32-bit values:

The setpoint value of the Series PD is contained in two registers. For example, register 76 contains the two

higher bytes, while register 77 contains the two lower bytes. The reverse of a read has to be performed. To write a

setpoint of 1250 degrees (which is really 1250.000) multiply the setpoint value (SP) by 1000. Add 65536 to negative

numbers. This produces the setpoint (SP) we want to send. To determine the most significant word (MSW), divide

the SP by 2

or 65536. To determine the least significant word (LSW), subtract from the SP the result of multiply-

ing the MSW by 2

SP = 1250 * 1000 = 1250000

MSW = 1250000 / 2^16 = 19

LSW = 1250000 - (19 * 2^16) = 4816

Scaling Factor - Multiplier or divisor for the parameter value.

Decimal Precision - Decimal precision is implied at three decimal places for integer values unless otherwise

noted.

All values used by the Series PD are integer values. Go to http://www.modbus.org for detailed information on the

Modbus TCP protocol.