Watlow PM LEGACY PM3 - Page 32

Watlow PM LEGACY
™
Limit Controller • 32 • Chapter 2 Install and Wire
Profibus DP Communications
485 T-/R-
+5Vdc Voltage Potential
VP
B
A
DG
trB
B
A
trA
Slot B & E
485 T+/R+
Digital ground
Termination resistor B
485 T+/R+
485 T-/R-
Termination resistor A
• Wire T-/R- to the A terminal of the EIA-485 port.
• Wire T+/R+ to the B terminal of the EIA-485 port.
• Wire Digital Ground to the common terminal of the EIA-485 port.
• Do not route network wires with power wires. Connect network wires in
daisy-chain fashion when connecting multiple devices in a network.
• A termination resistor should be used if this control is the last one on the
network.
• If using a 150 Ω cable Watlow provides internal termination. Place a
jumper across pins trB and B and trA and A.
• If external termination is to be used with a 150 Ω cable place a 390 Ω re-
sistor across pins VP and B, a 220 Ω resistor across pins B and A, and
lastly, place a 390 Ω resistor across pins DG and A.
• Do not connect more than 32 PM LEGACY™ Limit controllers on any giv-
en segment.
• Maximum EIA-485 network length: 1,200 meters (4,000 feet)
• 1/8th unit load on EIA-485 bus
• When termination jumpers are in place, there is 392 ohm pull up resistor
to 5V and 392 ohm pull down resistor to DP. There is also a 221 ohm re-
sistor between A and B.
• Communications instance 2
PM6[L,M] _ _J - [J,6] _ _ _ G_ _
Profibus
Terminal
EIA/TIA-485
Name
Watlow
Terminal Label
Function
VP (Voltage Poten-
tial)
- - - - VP +5Vdc
B-Line B B T+/R+
A-Line A A T-/R-
DP-GND common DG common
Profibus DP LED Indicators
Viewing the unit from the front and then looking on top of the controller two bi-color LEDs can be
seen where only the front one is used. Definition follows:
Closest to the Front
Indicator LED Description
Red Profibus network not detected
Red
Flashing
Indicates that the Profibus card is waiting for data exchange.
Green Data exchange mode