This guide contains the various connector specs and meter wiring instructions for the pulse input MDTs. We also show how our CIT software will identify each input type. The following battery and line powered model numbers are covered:
| TW-160/165 (B/L)-P(P) | Single/(Dual) Pulse input Standard Range |
| TW-160/165 (B/L)-P(P)T | Single/(Dual) Pulse with Time of Use option Std. Range |
| TW-170/175 B-P(P) | Single/(Dual) Pulse input Max Range |
| TW-170/175 B-P(P)T | Single/(Dual) Pulse with Time of Use option Max Range |
| TW-167/177 S P (L) | Single Submersible Pulse, optionally with Leak Detection Cable |
| TW-140(B/L)-P(P) | Single/(Dual) Pulse input (Older version) |
| TW-140(B/L)-P(P)T | Single/(Dual) Pulse with Time of Use option (Older version) |
| TW-140B-Y | Hersey Meter Compatible Single Pulse input (Older version) |
1. Polarity connection concerns
Most Water & Gas Meters:
The polarity does not matter for most Water and Gas meters which typically use a magnetic reed type switch.
Hersey, Zenner, & Some Badger Pulse Water Meters:
For these meters, connect the Red wire to the P1 input, and the black to COM.
Electric Meters:
The polarity is important for connecting to most Electric meters.
- The Pulse Input (P1 or P2) goes to the meter’s pulse output terminal, labeled variously WH+, P1, “+”, or ISOLATED OUTPUT 10/100/1000
- The Common input goes to the common terminal, variously labeled ISOL COM, “-“, or COM.
2. TW-160/165 and TW-170/175 MDTs
The TW-160/165 and TW-170/175 models of MDT use the standard 5mm removable connector. The unit is designed to have the metering wires run between the batteries (as shown in the picture below) and through the hole at the bottom of the unit. When mounted vertically on drywall (recommended), this allows a good drip loop to be formed.
2.a TW-160/165 /170/175 B-P Single Pulse Input MDTs
Includes TW-165B-H Hersey variation.
2.b TW-160/165 & TW-170/175 B-PP Dual Pulse Input MDTs
Note that you can swap the Meter connections and the polarity remains correct.
3. TW-167/177 S-P Submersible MDTs
The TW-167/177 submersible pulse MDTs do not have any wiring connectors. The wires are already connected within the epoxy potted case. Meters interface to the sealed MDT wires by using waterproof IDC Splice connectors (or similar) between MDT and the Meter. The wiring information is printed on each MDT, as shown here. If these will be used in pits, it is recommended to further waterproof the connections by plunging the IDC connections into a grease-filled pod.
4. TW-140 MDTs
4.a Newer TW-140 Single Pulse Input MDTs
Models manufactured after May, 2014
Serial Number greater than 81A0A000
4.b Newer TW-140 Dual Pulse Input MDTs
Models manufactured after May, 2014
Serial Number greater than 81A0A000
4.c Older TW-140 Single Pulse Input MDTs
Models manufactured before May, 2014
Serial Number less than 81A0A000
4.d Older TW-140 Dual Pulse Input MDTs
Models manufactured before May, 2014
Serial Number less than 81A0A000
Note! Single input Hersey Meter compatible MDTs use the P2 input connector; the P1 connector is not installed on TW-140B-Y units.
4.e Special Model Single Pulse Input
Rare, only 1000 made in May, 2014
Serial Number range 81A0A400 to 81A0A7FF
Connector Specifications
TW-160/165 & TW-170/175 Removable Connector Specs:
Used on all TW-160/165 and TW-170/175 MDTs Pulse MDTs. Connector is compatible with other transmitters and some meters in the market.
| Wire size (solid/stranded): | 14 to 22 AWG |
| Strip Length | 1/4 inch (6mm) |
| Blade Type | 2.5mm Flat |
TW-140 Removable Connector Specs:
Used on all MDT products sold after Q2/2014.
| Wire size (solid/stranded): | 16 to 26 AWG |
| Strip Length | 3/16 in (5mm) |
| Blade Type | 2.0mm Flat or Phillips 00 |
Connectors can come in green and blue colors. They are not interchangeable. MDT models with blue connectors must use the blue connectors and vice versa.
Spring Connector Specs:
Used on older MDT units as primary pulse input.
| Wire size (solid/stranded): | 20 to 26 AWG |
| Strip Length | 5/16 in (8mm) |
| Blade Type | Not Applicable |
| Wire size (solid/stranded): | 18 to 28 AWG |
| Strip Length | 3/16 in (5mm) |
| Blade Type | 1.5 to 1.8 mm Flat |