Product Details
The Honeywell PUL6438S, also cataloged as the PUL6438S Programmable Unitary Controller, operates as a dedicated hardware component for HVAC zone control and process variable execution within Spyder LonWorks network platforms.
Hardware Specifications
| Parameter | Specification |
|---|---|
| Model | PUL6438S |
| Brand | Honeywell |
| Origin | USA / As specified on hardware label |
| Weight | 1.34 lbs (0.61 kg) |
| Operating Temp | -40 to 65 deg C |
| Power Consumption | 24 VAC nominal supply voltage |
| Controller Series | Spyder |
| Total I/O Capacity | 21 Input/Output positions |
| Real-Time Clock | Integrated onboard real-time clock |
| Network Interface | Free Topology Transceiver (FTT) high-speed 78 kbps network |
| Auxiliary Bus / Sensor Port | Sylk Bus support; user access to airflow sensor inputs |
Cold Junction Compensation (CJC) and Channel-to-Channel Isolation
The PUL6438S features 21 discrete and analog input/output positions managed by dedicated processing channels to execute zonal temperature, airflow, and valve modulation algorithms. Signal conditioning circuitry provides robust channel-to-channel isolation across physical terminal terminals, preventing ground loop offsets during low-voltage temperature and pressure transmitter processing. For thermal instrumentation and airflow monitoring interfaces, high-accuracy cold junction compensation (CJC) reference networks stabilize input signal digitization across changing ambient temperature profiles.
Frequently Asked Questions
Q: What communication physical layer and protocol speed does the PUL6438S controller utilize?
A: The PUL6438S uses a Free Topology Transceiver (FTT) communication network operating at a fixed transmission rate of 78 kbps.
Q: How does the PUL6438S handle real-time scheduling and sensor bus expansion?
A: The unit incorporates an onboard real-time clock for time-stamped schedule execution and supports Sylk Bus integration for digital wall module and airflow sensor connectivity.
Field Installation Guidelines
- Mount the PUL6438S controller onto a standard 35 mm DIN rail or surface mounting plate inside a protective NEMA or IP-rated enclosure.
- Connect dedicated 24 VAC power conductors to the main power terminal block, keeping supply wiring separate from low-voltage I/O lines.
- Terminate FTT network cabling using approved twisted-pair wire, maintaining free topology wiring rules and verifying end-of-line termination requirements.
- Earth all cable shields at a single chassis ground busbar to mitigate electromagnetic interference on analog input channels.
Additional Information
- 100% Genuine Parts: All products are original and authentic, ensuring reliable industrial performance.
- 30-Day Refund Guarantee: Return any in-stock item within 30 days in original, unopened packaging for a full refund (excluding shipping and fees).
- 12-Month Warranty: Covers defects in materials or workmanship; excludes misuse, normal wear, or unauthorized modifications.
- Worldwide Shipping: We ship via USPS, UPS, FedEx, and DHL. Delivery times vary by country and may be subject to customs or import fees.
- Support & Contact: Technical and warranty assistance is available anytime. Contact us here: Contact.
- Purchase Guidance: Check product specifications and compatibility carefully before ordering to ensure proper application.





























