Programmable features for master mode, Serial communications – Precision Digital PD865 User Manual

Page 9

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PD865 Snooper Modbus

Serial Input Meter

Instruction Manual

9

Programmable Features for Master Mode

FUNCTION CODE Select which Modbus function code (03 or 04) to use in

reading the slave device.

NUMBER
OF PVs

Select the number of process variables to be polled by the
Master (PV1-PV8).

SLAVE ID

Assign the slave ID or address (1-247) containing the
process variables to be displayed (Slave ID for PV1-8).

REGISTER
NUMBER

5 digit: 30001-39999 or 40001-49999
6 digit: 300001-365536 or 400001-465536
Specifies which register(s) to read in the slave device.
Range is dependent on Function Code selection (04 or 03)
and digits selection (5 or 6).
PV2-PV8: Select 1 register for Short integer or 2 registers
for Long integer and Floating point data types.

DATA TYPE

Select the data format that the slave device uses. Select
between Short integer (2 byte) and Long integer (4 byte) or
floating point (4 byte), Signed or Unsigned (integer only)
and byte order (big-endian vs. little-endian).

POLL TIME

0.1 to 25.5 sec. Time between read-commands (Master
mode) or listening-time window (Snooper mode).

SLAVE
RESPONSE
TIMEOUT

0 to 25.4 seconds X3 (76.2 sec). Time allowed for the slave
to respond to a command. Programming 0 disables the
timeout. This setting is used by Master and Slave modes.

Serial Communications

SLAVE ID
OR ADDRESS

1 – 247. Specifies the ID or address of the slave device
(Master or Snooper mode) or the address of the PD865
(Slave mode).

BAUD RATE

300 – 19,200 bps

DATA

8 bit (1 start bit, 1 or 2 stop bits)

PARITY

None, even, or odd. 1 or 2 stop bits selectable for None.

BYTE-TO-BYTE
TIMEOUT

0.01 – 2.54 seconds

TURN AROUND
DELAY

Less than 2 ms (fixed)

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